Print hammer interposer and actuating means in flying printers

ABSTRACT

A flying printer having a plurality of printing columns disposed and supported between a pair of spaced main plates and having printer-driving means, timing and synchronization means and paper-feeding means disposed outside of said main plates and mounted thereon. The flying printer preferably includes a continuously rotating ratchet wheel having at least one tooth extending therefrom and a print drum rotated in synchronization with said ratchet wheel, both mounted between said main plates. Each printing column includes a trigger lever adapted for rotational and linear displacement, a print hammer adapted to effect printing in response to the linear displacement of said trigger lever and means including an electromagnet for selectively rotating said trigger lever into and out of the path of said ratchet wheel tooth, said trigger lever being linearly displaced when disposed in said path.

I United States Patent 13 598 046 [72] Inventor Shigeyoshi Hirabayashi 3,139,820 7/1964 Kittler 101/93 Nagano-ken, Japan 3,156,180 11/1964 Barnes 101/93 1211 Appl. No. 823,892 3,220,343 1 1/1965 Wasserman l0l/93 [22] Filed May 12,1969 3,292,531 12/1966 Mutz 101/93 [45] Patented Aug. 10, 1971 3,351,007 11/1967 Poland 101/93 [73] Assignee Kabushiki Kaisha Suwa Seikosha 3,420,166 1/1969 Ellis et al. 101/93 Tokyo, Japan Primary Examiner-William B. Penn pnomy 2:22 1 AttorneyBlum, Moscovitz, Friedman & Kaplan [31 43/31816 [54] PRINT HAMMER INTERPOSER AND ACTUATING MEANS [N FLYING PRINTERS 3 Claims, 4 Drawing Figs.

[52] U.S.C1 t 101/93 [51] Int. B4lj 9/36 [50] Field ot'Seareh 10l/93,93 C, 96; 197/133 [56] References Cited UNITED STATES PATENTS 2,766,686 10/1956 Fomenko et a1. 101/93 2,895,411 7/1959 Demer et a1. l0l/93 2,897,752 8/1959 Malmros et al.... 101/93 2,949,846 8/1960 Hoffman et a1. 101/93 3,123,195 3/1964 Hewitt et al. 197/133 ABSTRACT: A flying printer having a plurality of printing columns disposed and supported between a pair of spaced main plates and having printer-driving means, timing and synchronization means and paper-feeding means disposed outside of said main plates and mounted thereon. The flying printer preferably includes a continuously rotating ratchet wheel having at least one tooth extending therefrom and a print drum rotated in synchronization with said ratchet wheel, both mounted between said main plates. Each printing column includes a trigger lever adapted for rotational and linear displacement, a print hammer adapted to effect printing in response to the linear displacement of said trigger lever and means including an electromagnet for selectively rotating said trigger lever into and out of the path of said ratchet wheel tooth, said trigger lever being linearly displaced when disposed in said path.

PATENTED AUG] 0 s97:

SHEET 1 BF 3 FIG./

PATENTEU AUG] 01% 3, 598,046

sum 2 [1F 3 PATENTED AUG 1 0 19m 3, 598.046

sum 3 OF 3 PRINT HAMMER INTERPOSER AND ACTUATING MEANS IN FLYING PRINTERS BACKGROUND OF THE INVENTION This invention relates generally to flying printers utilized in electronic desk calculators and other numerical readout devices. In such printers, the hammer strikes a selected character from an array of characters provided in columnar fashion on the periphery of a continuously rotating print drum. However, the known arrangements of this type of printer have several substantial drawbacks. Specifically, shear will occur in the printing process if the contact time between the hammer and the print drum is too great, resulting in smudged printing or ripped paper. In order to overcome this defect, the contact time of the hammer with the character must be shortened, thereby increasing the operating speed of said hammer. In conventional printers of the type described, the hammer is directly operated by electromagnets, and an increase in the operating speed of the hammer requires. an in crease in the size and power of said electromagnets. However. an increase in the size and power of the electromagnets results in an increase in the volume of the printer and requires in creased electric power consumption, and is therefore un desirable. By utilizing the electromagnets to merely effect tim ing of the flying printer, rather than the actual direct operation of the hammer, the above described defects can be avoided while an extremely compact flying printer is provided.

Further, the known flying printers have occupied relatively large volumes of space and have proved difficult to maintain and repair. By mounting the printing columns between a pair of spaced main plates and disposing the peripheral equipment associated therewith outside of said plates, these defects can be avoided.

SUMMARY OF THE INVENTION Generally speaking, in accordance with the invention, a flying printer is provided wherein a plurality of print columns are disposed between a pair of spaced main plates. Rotatably mounted between said plates are a continuously rotating ratchet wheel having at least I tooth extending therefrom and a print drum rotated in synchronization with said ratchet wheel. Each printing column includes a trigger lever adapted for rotational and linear displacement, print hammer means adapted to effect printing in response to the linear displacement of said trigger lever and means for selectively rotating said trigger lever into and out of the path of said ratcht t wheel, said trigger lever being linearly displaced to effect printing when disposed in the path of said ratchet wheel tooth.

Said means for selectively rotating said trigger lever preferably includes an electromagnet, the electromapnets associated with each three adjacent print columns being disposed in a different plane, whereby three of said columns substantially occupy the space which would be occupied by one of said columns if all of said electromagnets were placed side by side.

Also mounted between said main plates are a plurality of support and guide members for supporting and guiding the elements of each column during the operation thereof. Disposed outside of said main plates and mounted thereon are printer-driving means, timing and synchronization means and paper-feeding means. The driving means preferably includes a motor and a gear train interconnecting said print drum and said ratchet wheel. The timing and synchronization means preferably includes signal generator means mounted on each of said ratchet wheel and print drum for generating timing and reset pulses and detecting means responsive thereto.

The paptrfccdrng means preferably includes an clcc ttomngnct opcrrttrvc in response to said r'csct pulses and adapted to ndvancc said pnpcr incrementally after one cycle of said print d rum.

Accordingly, it is an object of this invention to provide an extremely compact flying printer adapted to print extremely clear characters.

Another object of the invention is to provide a flying printer which is readily maintained and serviced.

Still other objects and advantages of theinvention will in pan be obvious and will in part be apparent from the specification.

The invention accordingly comprises the features of construction, combinations of elements, and arrangements of parts which will be exemplified in the constructions hereinafter set forth, and the scope of the invention will be indicated in the claims.

BRIEF DESCRlPTlON OF THE DRAWINGS For a fuller understanding of the invention, reference is had to the following description taken in connection with the accompanying drawings, in which:

FIG. I is a top plan view of a flying printer according to the invention, with portions broken away;

FIG. 2 is a sectional view taken along lines 2-2 of FIG. I showing one column thereof with the electromagnet associated therewith in the deenergized state;

FIG. 3 is a sectional view taken along lines 2-2 of FIG. I with said electromagnet energized and said column disposed in the printing position; and

FIG. 4 is a side elevational view of the flying printer of FIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawings, the flying printer according to the invention includes a plurality of print columns, one of which is shown in FIG. 2. The column includes a print hammer I mounted on one arm of an L-shaped hammer lever 2. Said hammer lever is pivotably mounted at the corner defined by the arms thereof on hammer lever shaft 3. Disposed immediately below hammer I is print drum 4 having characters spaced on the peripheral surface thereof. Said print drum and a print drum gear 5 are mounted on print drum shaft 6 for rotation therewith. Shaft 6, which defines the axis of said print drum is disposed immediately below the position assumed by hammer 1 when it strikes said print drum, whereby said hammer is disposed normal axis when striking said print drum. As shown in FIG. I, print drum gear 5 meshingly engages intermediate pinion 7 for the rotation of said pinion and intermediate gear 8 fixed thereto. Said intermediate gear, in turn, meshingly engages with ratchet gear 9 for the rotation of ratchet wheel I0. Said ratchet wheel is shown formed with a single tooth II but could be formed with a plurality of circumferential teeth if desired. The gear ratio between gears and pinions S, 7, 8 and 9 is selected so that the pitch time of tooth I1 equals the circumferential spacing of the characters on the peripheral surface of print drum 4. Thus, each rotation of tooth 11 corresponds to the advancing of one character on said print drum.

First and second trigger lever guide pins I2 and 13 are pro vided disposed on either side of trigger lever I4. Said trigger lever is formed with a tail portion I5 and a projection I6. Trigger lever I4 is adapted for pivotal and linear displacement and trigger lever guide member 18, formed with a plurality of grooves 41 defined by walls 42 for receiving said trigger lever, is provided to guide said trigger lever during said displacement. A spring I9 is secured between lever I4 and a fixing point 20 for biasing said trigger lever out of the path of tooth II. The end of arm 21 of hammer lever 2 is disposed to be engaged by shoulder 22 of trigger lever 14 upon the linear displacement of said trigger lever to pivot said trigger lever, whereby hammer I strikes print drum 4. Timing lever 23 is disposed to engage tail I5 of trigger lever I4 and is pivotably mounted on tinting lever shaft 24. Fixed to said timing lever is magnetic plate 25 adapted to cooperate with an clcctromag net :0 for the pivoting of said magnetic plate and timing lever in response to the activation of said electromagnet. A spring (not shown) is preferably mounted between the corner of hammer lever 2 and fixing point 29 to normally bias said hammer lever in the position shown with hammer I spaced from print drum 4.

Each print column thus includes a hammer 1, a hammer lever 2, a trigger lever 14, a trigger lever spring 19, a timing lever 23, a magnetic plate 25, an electomagnetic 26, and a hammer lever spring. As more particularly shown in FIG. 2, the columns are mounted in side-by-side relation between a pair of main plates 50 and 5]. The flying printer is preferably provided with a single print drum 4, ratchet wheel having a single tooth I], first and second guide pins 12 and I3, trigger lever guide member I8, trigger lever stopper l7, and timing lever shaft 24, all of which extend between said main plates. A motor 52, mounted on the outside of plate 51, is provided to drive ratchet wheel 10, which in turn drives print wheel 5 through gears and pinions S, 7, 8 and 9. The latter gear train is mounted outside of plate 50.

While hammer lever 2, trigger lever 14 and timing lever 23 are relatively thin, the'electromagnets 26 are relatively bulky. In order to permit the compact mounting of the components of the flying printer according to the invention, said clec tromagnets are disposed in three banks, as more particularly shown in FIG. 2. The electromagnets associated with one of each three adjacent columns forming said flying printer are disposed in a single bank, each of said banks of electromagnets being disposed in a different plane, so that space equal to the width of three columns is provided for each electromagnet. The angle defined between magnetic plate 25 and timing lever 23 is selected in each column according to the disposi tion of the electromagnet associated therewith-Thus, referring to FIG. I, the electromagnet 26 associated with columns a and b are in one bank, the electromagnets associated with columns c and d are in a second bank, while the electromagnets associated with columns g and iare in a third bank.

Also extending between main plates 50 and 51 are a paperfeeding roller 53 and guide frames 54 and 55 adapted to guide paper through said flying printer between hammer I and print drum 4. An inked ribbon would also be fed therebetween.

Turning now to the operation of the flying printer according to the invention, reference is bad to FIGS. 2 and 3. When the flying printer is activated but no timing signals are applied to the electromagnets or to the mechanism for advancing the paper, motor 52 continuously rotates ratchet wheel it) in the direction of arrow 32, thereby also rotating print wheel 4 in the manner described above. Said print wheel rotates in the same direction as said ratchet wheel. The rotation of tooth I I of said ratchet wheel follows a path defined by phantom line 33. In the absence of any signal energizing electromagnet 26, the column is disposed as shown in FIG. 2 with erd 34 of trigger lever 14 disposed outside of the path' of tooth II and maintained in that position by spring 19. When so disposed, trigger lever 14 is positioned by means of second trigger lever pin I3 and trigger lever guide member 18. Magnetic plate 25 is also maintained spaced from electromagnet 26 by spring 19 acting through tail of said trigger lever which eng: ges tim ing lever 23.

In order to print a character, a pulse signal is a; plied to electromagnet 26 immediately before the desired character on the peripheral surface of print drum 4 passes under hammer I. The activation of said electromagnet rotatably displaces mag netic plate toward said electromagnet, carrying timing lever 23 therewith. Said timing lever engages the tail 15 of trigger lever 14 to rotate said trigger lever in the counter clockwise direction about trigger lever guide member 18. When so disposed, end 34 of said trigger lever lies in the path of tooth I1, whereby it may be linearly displaced in the direction of arrow 37 thereby.

The linear displacement of trigger lever 14 is transmitted to arm 21 of hammer lever 2 by means of shoulder 22 of said trigger lever. Said hammer lever is in turn rotated in a counter clockwise direction causing hammer I to strike the print drum through inked ribbon 31 and paper at the moment that the desired character is positioned under said hammer. The olumn is shown disposed in this position in FIG. 3.

At this point in the cycle, it is necessary to rotate hammer lever I4 in the clockwise direction to bring end 34 thereof out of the path 33 of tooth II before said tooth completes a single.

revolution. If this is not done, the trigger lever will be linearly displaced in the direction of arrow 37 a second time during the next revolution of ratchet wheel 10, resulting in the double striking of hammer I on a single line. Several features of the flying printer according to the invention contribute to this result. The first of these is trigger lever stopper I7 which is struck by projection 16 on trigger lever 14 immediately before hammer l strikes the character so that trigger lever 14 rebounds in the direction of arrow 38 before the return of hammer lever 2 to its original position. The striking of projection 16 against trigger lever stopper 1? also serves to rotate said trigger lever in the clockwise direction during the return thereof to its initial position to bring end 34 of said trigger lever out of the path of tooth II. Also contributing to this rotation is spring I9 which tends to return said trigger lever to its original position with the inner surface of shoulder 22 resting against trigger lever guide member 18 and end 34 of said trigger lever out of the path of tooth I 1.

Turning now to FIGS. I and 4, the overall operation of the flying printer according to the invention will be described. Rotor shaft 56 of motor 52, upon which ratchet wheel 10 is mounted, carries at one end thereofoutside of main plate 50 a position detector having at least one magnet I0] mounted on the peripheral surface thereof which generates timing signals with every rotation, said timing signals being detected bya magnetic pickup head 102 mounted on plate 50.

As described above, rotation of rotor shaft 56 and ratchet wheel 10 is transmitted to print drum 4 for the rotation thereof in synchronization with said ratchet wheel through gear train 5, 7, 8 and 9. One rotation of ratchet wheel 10 equals the ad vancing of print drum 4 one character. Thus, if there are I6 characters circumferentially spaced about print drum 4, ratchet wheel I0 will rotate 16 times for every rotation of print drum 4. Mounted on one end of shaft 6, which carries said print drum, is position detector I03, also provided with at least one magnet in the peripheral surface thereof to provide timing signals for detection by magnetic pickup head 104 mounted on the outside of plate 50.

The timing signals detected by magnetic head I02 are preferably counted by a suitable pulse counter which operates in conjunction with a coincidence circuit adapted to compare the input signals from the circuitry of the desk calculator or other device to which the printer is connected with the detected signal. When coincidence is detected, the electromagnet associated with said circuit is energized to effect printing. The timing signals detected by magnetic head 104 are used for resetting the flying printer to permit printing of the next line. Said reset signal provides clock pulses to suitable controlling circuitry which permits both the resetting of the character counter and the energization of paper-feeding electromagnet 105 which displaces hooked lever 106 to rotate ratchet I07 and paper-feeding roller 53 to advance said paper by one line. Hooked lever I08 prevents the reversal of ratchet I07.

It has been found that a flying printer constructed in ac cordance with the invention offers substantial advantages over the prior art. Thus, although printing is performed during the continuous rotation of the print drum, the period of dwell of the hammer is shortened and clearly printed characters are obtained. The arrangement minimizes the wear on the trigger lever utilized to transmit energy to the hammer, giving such trigger lever an extremely long life. Since said trigger lever is preferably formed from a material of great stiffness, the operation of the arrangement results in a relatively l0w-energy loss during high-speed operation. Further, the arrangement avoids the defects of double striking, and provides an arrangement which is readily serviced.

Further, the arrangement according to the invention provides a device which consumes relatively little electric power, while utilizing a single motor to drive the entire mechanism including both the ratchet wheel and print drum. The arrangement according to the invention in effect, converts the rotational kinetic energy stored in the ratchet wheel to linear encr gy by the unique action of the trigger levers which are pulsive ly actuated by the rotating tooth to provide a large amount of mechanical energy to the print hammers without requiring large electromagnetsv In addition, arrangement is extremely compact and readily serviced, the peripheral equipment such as the motor, timing and synchronization means and paper advance means all being readily accessible since they are mounted outside the main plates.

It will thus be seen that the objects set forth above, among those made apparent from the preceding description, are efficiently attained and, since certain changes may be made in the above construction without departing from the spirit and scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense lclaim:

L A flying printer comprising a pair of substantially rectangular main plates; a print drum rotatably mounted between said main plates; a ratchet wheel having at least one tooth extending therefrom rotatably mounted between said main plates; a plurality of printing columns disposed in side-by-side relation between said main plates, each of said printing columns including a substantially L-shaped hammer lever adapted for pivotal displacement substantially about the junction of its two arms, a hammer mounted on one of said hammer lever arms for striking said print drum upon the displacement of said hammer lever to effect printing; a separate trigger lever adapted for rotational and linear displacement; means for rotatably displacing said trigger lever into and out of the path of said ratchet wheel tooth including a timing lever for rotatably displacing said trigger lever into said path, said trigger lever being positioned for linear displacement when in the path of said ratchet wheel tooth to strike the other arm of said L-shaped hammer lever for the rotational displacement of said hammer lever to effect printing; electromagnetic means positioned relative to said timing lever for the displacement of said timing lever when actuated, to in turn displace said trigger lever into the path of said ratchet wheel tooth; driving means for synchronously and continuously rotating said ratchet wheel; timing and synchronization means for governing the operation of said flying printer; paper guide means; and electrically actuated plunger means for driving said paper guide means for paper feeding, the L-shaped print hammers and trigger levers of the respective printing columns being substantially aligned in sideby-side relation, said print drum, ratchet wheel, paper guide means and trigger levers being positioned substantially in the region between said L-shaped hammer lever arms, said plunger means, timing and synchronization means, and driving means being mounted outside of said pair of main plates.

2. A flying printer as recited in claim 1 wherein said timing and synchronization means includes a wheel mounted for rotation with said ratchet wheel, at least one permanent magnet disposed in the surface of said wheel for rotation about the axis thereof, and pickup means for generating timing signals as said magnet is carried thereby for use in the selective actuation of said electromagnetic means, displacement of said timing lever and printing.

3. A flying printer as recited in claim 2 including a further wheel mounted for rotation with said print drum, at least one further permanent magnet disposed in the surface of said further wheel for rotation about the axis thereof, and further pickupmeans for generating reset signals in response to the passagethereby of said further permanent magnet, said reset signals being applied for the actuation of said plunger means. 

1. A flying printer comprising a pair of substantially rectangular main plates; a print drum rotatably mounted between said main plates; a ratchet wheel having at least one tooth extending therefrom rotatably mounted between said main plates; a plurality of printing columns disposed in side-by-side relation between said main plates, each of said printing columns including a substantially L-shaped hammer lever adapted for pivotal displacement substantially about the junction of its two arms, a hammer mounted on one of said hammer lever arms for striking said print drum upon the displacement of said hammer lever to effect printing; a separate trigger leveR adapted for rotational and linear displacement; means for rotatably displacing said trigger lever into and out of the path of said ratchet wheel tooth including a timing lever for rotatably displacing said trigger lever into said path, said trigger lever being positioned for linear displacement when in the path of said ratchet wheel tooth to strike the other arm of said L-shaped hammer lever for the rotational displacement of said hammer lever to effect printing; electromagnetic means positioned relative to said timing lever for the displacement of said timing lever when actuated, to in turn displace said trigger lever into the path of said ratchet wheel tooth; driving means for synchronously and continuously rotating said ratchet wheel; timing and synchronization means for governing the operation of said flying printer; paper guide means; and electrically actuated plunger means for driving said paper guide means for paper feeding, the L-shaped print hammers and trigger levers of the respective printing columns being substantially aligned in side-by-side relation, said print drum, ratchet wheel, paper guide means and trigger levers being positioned substantially in the region between said L-shaped hammer lever arms, said plunger means, timing and synchronization means, and driving means being mounted outside of said pair of main plates.
 2. A flying printer as recited in claim 1 wherein said timing and synchronization means includes a wheel mounted for rotation with said ratchet wheel, at least one permanent magnet disposed in the surface of said wheel for rotation about the axis thereof, and pickup means for generating timing signals as said magnet is carried thereby for use in the selective actuation of said electromagnetic means, displacement of said timing lever and printing.
 3. A flying printer as recited in claim 2 including a further wheel mounted for rotation with said print drum, at least one further permanent magnet disposed in the surface of said further wheel for rotation about the axis thereof, and further pickup means for generating reset signals in response to the passage thereby of said further permanent magnet, said reset signals being applied for the actuation of said plunger means. 